Solana: 10 Facts You Didn't Know About the Concentrated Solar Power Plant Near Gila Bend

Solana, the giant concentrated-solar plant near Gila Bend, began commercial operations on Monday that will deliver power to Arizona residents for the next 30 years.

You've certainly seen the rows and rows of mirrors in the last year or so if you've driven the Gila Bend route on the way to San Diego. And you've heard Solana, built by Spain's Abengoa company, is unlike other solar plants because it can generate electricity even when the sun's not overhead.

Much has been written about the $2 billion project. But here are 10 facts about it you probably haven't heard:

Image: abengoasolar.com

10.) First, some basics: The plant works by using mirrors to focus on pipes that contain a liquid. This super-hot liquid gets transferred for direct use in two electricity-producing steam turbines, and also sent to chambers of molten salt, which retain the heat long enough to drive the turbines for six hours after a day's charging.

Keeping things as green as possible, even this molten heat-transfer fluid is non-toxic. It's so harmless, in fact, you could actually eat it.

"It wouldn't taste very good," confesses Jim McDonald, APS spokesman.

You'd have to blow on the stuff awhile to cool it down before trying to take a gulp. The fluid is never allowed to drop below 530 degrees Fahrenheit.

9.) Solana should have been operational before now. Though Abengoa announced it would build the plant back in 2008 and received subsequent approval from the Arizona Corporation Commission, it took longer than expected to find financial backers. Little thing called the Great Recession had something to do with it. A story back then in the Phoenix Business Journal states the plant would be operational by "early 2013." Later stories, including some from earlier this year, talked about a June or August start, but that didn't happen, either. But delays are nothing but bad memories with the plant up and running as of this week.

Image: Ray Stern

8.) Concentrated solar power is more hazardous than photovoltaic solar plants.

Neither kinds of power source emits lead, sulfuric acid or any other kind of substance that might be hazardous to the public. Workers, however, face several kinds of risks at Solana.

Naturally, employees of any electric plant might be electrocuted if they're not careful. But Solana employees -- about 85 people are needed to operate the plant -- need to pay attention to safety risks associated with the two 140-megawatt steam turbines, because steam can kill. Another danger, according to published reports: The heat-transfer fluid in the CSP plants might blow up and start a fire.

7.) Solana has a lot of mirrors -- more than 900,000. If you broke every one, you'd have more than 6.3 million years of bad luck.

So don't try it.

Image: Google Books

6.) Concentrated solar power is an old idea. One setup was patented by Robert H. Goddard, father of rocketry. He wrote about his ideas in a 1929 Popular Mechanics article now available on the Internet.

5.) For the plant to work, it needs to use about 10 percent of the power it generates. That's why you may have seen the different megawatt-capacity ratings for the plants, usually given in published reports as 250 or 280. The difference is that the extra 30 megawatts is used to operate the plant, officials say.

Image: Ray Stern

4.) The plant outputs only 38 percent of its rated capacity over the year. But that's actually really good for solar.

Baseload plants pump out something near their capacity rating for 24 hours a day, if need be. On earth, solar plants need their beauty sleep at night. Most solar plants only generate about 20 percent of their rated capacity over a year. But Solana generates its 38 percent because of the extra energy stored in the molten-salt tanks.

3.) In the winter, photovoltaic kicks concentrated solar's butt.

Solana generates clean power equivalent to that used by about 76,000 homes for a full 18 hours a day, APS says. During peak loads, when PV solar production begins to wane, Solana's power keeps on coming, offsetting power from expensive, polluting natural-gas plants. But that's during the summer.

In the cold, shorter days of winter, Solana only generates juice for about eight hours a day, approximately two hours less than the winter productivity of photovoltaic plants, APS data shows.

Image: Ray Stern

2.) Economics 101 teaches that when a massive new supply of something enters the market, the price of that thing should drop. Not so with solar power. As you probably have heard, being green is expensive.

Solana will add about $1.28 a month to the bills of each typical APS customer, according to APS. After five years, that goes down to $1.09 a month, and after 10 years, it'll be 94 cents a month.

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Yet the plant emits zero pollution -- a valuable benefit. It's a steal when you compare it to net metering, which APS claims costs ratepayers about $1.21 a month for about 18,000 rooftop solar customers now, but will be even more expensive in the future.

Ray Stern has worked as a newspaper reporter in Arizona for more than two decades. He's won many awards for his reporting, including the Arizona Press Club's Don Bolles Award for Investigative Journalism.